The invention relates to a method for processing film images which are extracted from a film recording beam path of a moving image camera, and to an apparatus for carrying out the method.
DE 103 01 714 A1 discloses a method for processing film images that are extracted from a film recording beam path of a moving image camera and are fed to an image sensor. The image sensor is arranged in an assist beam path of the moving image camera, said assist beam path being interrupted periodically depending on the image recording frequency of the moving image camera, converts the film images into digital assist signals and outputs them to a data processing device with an image frequency matching the image recording frequency of the moving image camera. The data processing device processes assist images derived from the digital assist signals with the image recording frequency of the moving image camera and outputs the digital assist signals for display of the assist images with an assist image frequency or the image recording frequency of the moving image camera to a digital storage device or for display of the assist images with a normalized image frequency, for example 24 images/s, to a monitor.
A video assist system disclosed in U.S. Pat. No. 4,928,171 for eliminating or reducing the image flicker that results from the periodic interruption of the recording beam path of the moving image camera depending on the image recording frequency of the moving image camera controls the video image sensor in a light-sensitive manner only when light is available in the video beam path, and stores the video signals of the video image sensor at the frequency of the video image sensor in a buffer memory. The video signals are read out from the latter with a standard-conforming video signal frequency, such that, independently of the film transport speed or image recording frequency of the moving image camera, the video output signal corresponds to the standard-conforming video image frequency and therefore does not deal with the peculiarities in the exposure of a moving image film.
By contrast, the method disclosed in DE 103 01 714 A1 enables film images extracted from a film recording beam path of a moving image camera to be processed in a manner adapted to the peculiarities of a moving image camera. In this case, for standard-conforming conditioning of the video signals for flicker-free representation of video frames or video fields, a digital assist image is generated in parallel with each film image and is recorded in real time, that is to say at the film transport speed of the moving image camera, and can be represented in real time or any other viewing speed. This ensures an entirely satisfactory representation of special effects generated by the moving image camera, such as slow-motion and quick-motion recordings.
In further video assist devices disclosed in the prior art, such as, for example, the video assist control system for a plurality of cameras that is disclosed in U.S. Pat. No. 6,353,461 B1, the data transmission from the camera or cameras is effected in analog fashion as a standard video signal, which later is digitized in a computer, so that no digital assist signals are generated in this case. Consequently, the resolution is fixed at the resolution defined in standard video of, for example 624 lines in standard PAL video and slow-motion and quick-motion effects cannot be cleanly processed and represented.